Bringing Life to the Shoreline at the Fremont Bridge

Bringing Life to the Shoreline AT THE FREMONT BRIDGE

Alicia Kellogg

MLA Capstone Project, June 2021 1

Introduction

The Fremont Bridge is one of six bridges spanning the Ship Canal in Seattle between Puget Sound and Lake Washington. It was constructed in 1917 to span the then newly-constructed Lake Washington Ship Canal, a modern engineering marvel built to make waterbound passage between Puget Sound and the interior fresh water bodies more tenable.

By digging a canal from the Sound to Lake Washington, Seattleites completely changed local hydrology and “cut” the city in two, thereby creating the need for bridges in order to cross the waterway.

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Today, the Fremont Bridge is a colorfully painted neighborhood icon, one of the few human-scale bridges for pedestrians and bikes alongside car and bus traffic. Its proximity to the Burke Gilman, the South Ship Canal trail, and the Cheshiahud Lake Union Loop make it a popularly traversed bridge by commuters and recreationalists alike.

Interesting features at this site include fenders for boat traffic, brand new bioretention cells installed nearby at the northern base of the Aurora Bridge, and small portions of the bank that are armored with rip rap instead of concrete walls.

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Project Origins

This design project was inspired by an existing research effort called the Sweetgrass Restoration Project, which focuses on strategies that create living shorelines in urban waterways in order to increase salmon habitat.

Concept Development SWEETGRASS RESTORATION PROJECT

LIVING SHORELINES

PROJECT LOCATION

FREMONT BRIDGE

+ = LIVING SHORELINES AT FREMONT BRIDGE

Final Project Concept

BRINGING LIFE TO THE SHORELINE AT FREMONT BRIDGE 4

FREMONT BRIDGE

Design Question What design interventions can reveal, connect, and enhance life to the shoreline at Fremont Bridge?

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FREMONT CANAL PARK

GOOGLE PARK VIEW

EVANSTON PLAZA

0.5-MIL E

WALKS HE

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FREM

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I A BR

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project site passage places of rest 6

Rest-Passage Analysis

Due to its proximity to the Burke-Gilman Trail, the project site has a narrow, elongated quality that encourages passage rather than rest. This diagram shows how passage-dominant the surrounding areas along the shoreline are to the east and west of the site.

To the east There are a few small spaces available for rest to the east of the site, but all are liminal and insubstantial.

Fremont Canal Park is difficult to recognize as a park because it is really just a long, narrow stretch of lawn between the trail and the canal. There are a few formal benched areas for sitting;

during sunny weather, residents can be seen picnicking on blankets or lawn chairs that they’ve brought from home.

Google Park View and Evanston Plaza are both terraced seating areas between buildings that are popular when it’s sunny out, especially for local workers during lunch breaks.

To the west Gasworks Park is just outside the halfmile walkshed to the west. Between this project site and Gasworks, there are no formal opportunities for rest.

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salmon migration route elevated water temp and DO issues

R IVE MAMISH R M SA

artificial nighttime light issues

PUGET SOUND

FREMONT BRIDGE

LAKE WASHINGTON

LAKE SAMMAMISH

DA R RIVER

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QUAH CRE SA EK

IS

CE

Salmon Migration Issues

The anadramous salmonid species that migrate through the Ship Canal are Chinook, coho, and sockeye. Each of these salmon runs originates in either Issaquah Creek or the Cedar River, both of which are increasingly urban the closer they get to Puget Sound.

The highly developed nature of these migration routes approaching Puget Sound results in increasing existential threats to juvenile salmonids.

from predators, and healthy riparian vegetation that provides dapple shade for camouflage and food inputs in the form of terrestrial insects.

The Ship Canal is the final urban gauntlet that outmigrating juveniles must pass through before reaching the Sound.

Suboptimal habitat conditions include armored shorelines, a proliferation of overwater structures, and a high density of invasive predators.

Migratory salmon have relatively straightforward habitat needs in fresh water. Outmigrating juvenile salmonids require: cool, clean water with plenty of dissolved oxygen, stream channel complexity to provide cover 9

CONCRETE WALL Armoring that exte Ship Canal ends on

BURKE-GILMAN TR

A popular urban tra cyclists, skaters an proximity to this tra

Existing Site Conditions 10

ends through most of the n the west side of the bridge.

RAIL

ail for walkers, runners, nd commuters, the site’s ail makes it highly visible.

CREOSOTE FENDERS Boat fenders create a uniquely protected shoreline, suggesting site boundaries to the east, west, and in-water. They also provide opportunities for anchoring and containment.

DEGRADED VEGETATION Patches of weeds and non-native plants contribute to the site’s lack of identity and present an opportunity for urban restoration.

RIP RAP Rip rap creates a gradual, eased-slope shoreline compared to the concrete walls that dominate the rest of the canal.

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Deriving Design Principles

Proposed Improvements

Existing Conditions

Salmon

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Humans

Creosote fenders leach toxins into the water

Armored shorelines eliminate places to hide from predators

Degraded vegetation attracts fewer terrestrial insects as food source

No ways to interact with or understand urban ecological processes

Narrow or limited places for rest, relaxation, and observation

Homogeneity along trail, no unique site identity

Remove toxins to improve water quality

Add complexity to provide protection from predators

Install native plants that mimic riparian conditions

Create opportunities to increase ecological literacy

Create places to rest rather than just passing through

Build a sense of place that is congruent with neighborhood

Design Goals Create habitat for salmon (and other urban wildlife) that provides the provide protective

mimic riparian

habitat

conditions

functions of natural riparian systems Create “habitat” for humans to provide a place of rest and encourage them to slow down and pay attention to urban

create places

build a sense

to rest

of place

waterways and urban wildlife Reveal, heal, and highlight the connections between water and land,

increase ecological

improve water

literacy

quality

city and nature, human and animal

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6 10 9

Schematic Design

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8 5

8 4 9

1

2

3 9 6 7

10

5

0 14

100

200

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restored plantings

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exclusionary fencing

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sidewalk art

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live salmon count sign

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interpretive signage

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places of rest

of place

for salmon

habitat mats

build a sense

to rest

for humans

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create places

literacy

heal, and

floating wetlands

increase ecological

conditions

Create habitat

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mimic riparian

habitat

Create “habitat”

gabion fender

provide protective

quality

Reveal,

1

improve water

bridge bioretention

connections

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highlight

10 welcome arch

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Kit of Parts

The Fremont Bridge is a unique site, but its individual components are not uncommon to urban waterways. This project’s schematic design can be broken up into a kit of parts where each design intervention addresses site conditions that may be found in other parts of the Ship Canal, Seattle, or any other similar urban site.

The ultimate goal of this site design is to create a whole, cohesive site with its own identity - examining the specifics of each intervention can help understand how they will work together to create a complete and distinct site.

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Gabion Fenders

A double wall of 39” tall gabions will help to break wave action, allow walking access for floating wetland maintenance, and create habitat for fish, insects, and aquatic plants.

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Floating Wetlands

Low-tech floating wetlands made out of readily accessible materials attract terrestrial insects and help improve water quality. Modular and small in size, these units can be installed and maintained easily.

Create habitat for salmon

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TENSAR CAGE

Limits fowl browse

EMERGENT PLUGS Juncus tenuis Eleocharis palustris Schoenoplectus acutus

TENSAR LID PANEL

Compacts/contains substrate

PUMICE BRICKS Flotation element

WOODSTRAW

Growing substrate for emergent plugs

TENSAR CRIB

Lightweight and flexible, contains the substrate and allows plants to grow

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Create habitat for salmon

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Habitat Mats

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Partially-submerged envelopes of tightly-gauged coir fabric wrapped around woodstraw help soften the shoreline without disturbing existing conditions.

Restored Plantings

Beautiful native plantings become an aesthetic feature for humans and functional habitat for terrestrial insects.

Woody evergreen plants help screen and fence access to the water for safety.

Desired Plant Qualities SCREENING

• Prevents unsafe access to water • Discourages litter

ATTRACTIVE

• Contributes to site character • Encourages rest

NATIVE EMERGENT PLUGS Juncus tenuis Eleocharis palustris Schoenoplectus acutus

• Attracts terrestrial insects • Minimizes maintenance needs • Grows well with other natives

Planting Palette

COIR ENVELOPE

Compacts/contains substrate

WOODSTRAW

Growing substrate for emergent plugs

LUMBER FRAME

Provides rigidity and flotation

Evergreen Huckleberry Vaccinium ovatum

Dull Oregon Grape Mahonia nervosa

Baldhip Rose Rosa gymnocarpa

Nootka Rose Rosa nutkana

Salal Gaultheria shallon

Sword Fern Polystichum munitum

COIR ENVELOPE

Compacts/contains substrate

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Exclusionary fencing that reaches all the way to the ground has a small enough gauge to let juvenile salmonids through, but not their predators like northern pikeminnow, smallmouth bass, or largemouth bass.

Juvenile Salmonids baby Chinook

baby Coho

Sidewalk Art

Permanent illustrations painted onto the Burke-Gilman indicate entry to the site and break up trail monotony.

Painted juvenile salmon approach from the east while spawning adults approach from the west, highlighting the salmon migration that usually goes unseen.

Create habitat for salmon

Exclusionary Fencing

Excluded Predators Northern pikeminnow

Smallmouth bass

Largemouth bass

Approaching from the west

Approaching from the east

Create “habitat” for humans

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Live Salmon Count Sign

Referencing the pedestrian/bike count on the Fremont Bridge above, this live digital sign will indicate important real-time information about what’s happening in the water.

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Interpretive Signage

Educational signage will show the relationship between urban stormwater and water quality, and why our awareness about urban wildlife is important.

URBAN WILDLIFE Great Blue Heron

Create “habitat” for humans

Cormorant

Beaver

Salmon

SALMON CAM

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Places of Rest

Pull-outs along the Burke-Gilman with toadstool seats reinforce the shoreline shape and verticality while encouraging people to slow down and pay attention to the landscape before them.

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Welcome Arch

Arch-shaped art installations at either end of the site indicate entry into a distinct space, plus they create photo opportunities of the iconic bridge behind.

Create “habitat” for humans

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Bridge Bioretention

Stormwater collected by the bridge above is piped into beautifully-landscaped bioretention cells that recall the plant palette and design of the Aurora Bridge bioretention. Their shape helps extend the shoreline back towards land while creating a pocket of space for people to gather and rest. Painted lines on the pavement help show the unseen flow of water through underground pipes, revealing the obscured stormwater management practices.

CONTRIBUTING AREA

Stormwater runoff from the bridge on-ramp gets piped to the biortention for filtration

Reveal, heal, and highlight connections 22

DOWNSPOUT

Directs stormwater runoff into bioretention cells

UNDERGROUND PIPE

Filtered stormwater gets piped underground and drains to the Ship Canal

BIORETENTION CELLS

Stormwater flows through terraced bioretention cells, filtering out pollutants

CORTEN STEEL

Matching materiality to the Aurora Bridge bioretention cells helps add continuity with surrounding landmarks

Enhancing Salmon Habitat

HABITAT MATS

NATIVE PLANTS

FLOATING WETLANDS

EXCLUSIONARY FENCE GABION FENDER 23

Enhancing Human “Habitat”

SIDEWALK ART

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INTERPRETIVE SIGNAGE

PLACES OF REST WELCOME ARCH LIVE SALMON COUNT SIGN

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Notes From the Designer

I have lived in Fremont for several years, and this site is near and dear to my heart. I have seen great blue herons, cormorants, bunnies, and once I even saw a beaver(!) at this site. I have stopped to watch the bridge open with other passers-by, snapping the picture you’ll see on the back cover of this booklet.

Designing this capstone project has been a wonderful opportunity for me to envision what I want my neighborhood to look like.

Discussion Many of the opportunities at this site created unique design challenges. While the inclusion of- and proximity to- the Burke Gilman meant a lot of foot traffic 26

and high visibility, it was also important to me to make sure the trail remained unobstructed and accessible, which was diffucult with limited site width.

Additionally, the long, narrow shape of the area resulted in a site design whose features are best understood at a crosssection rather than longitudinally, which does no favors to the human experience.

Deciding to design a “kit of parts” was fraught for me; I think the failure of a lot of urban green stormwater solutions is this idea that a universal design could miraculously solve all urban environmental woes. The green stormwater infrastructure projects I have been a part of have required a high degree of customization to be effective, and

seem to resist standardization. I didn’t want to imply universality with a kit of parts, but I did want to suggest that my design interventions could be launching points for solving problems in similar contexts. I tried to avoid designing too specifically and instead focused on the broad strokes of how intervention ideas could be used as part of larger design goals.

Conclusion A challenge of any site design that attempts to incorporate ecological improvements is that nature isn’t something that can be modularized.

Ecology follows systems, connections, and relationships, and doesn’t easily fit

While most of the design interventions in the kit of parts are infeasible due to funding, bureaucracy, or pure physics (apologies to any fans of the gabion fender!), there are projects being implemented today that have already pushed the envelope regarding design, collaboration, and green stormwater infrastructure. The bioretention cells near the Troll at the Aurora Bridge are an inspiring example of a project whose beauty and functionality are evenly balanced, and whose impact is equal This design project is ultimately a visioning parts anthropocentric and ecological. exercise in how we can re-conceptualize Although my project will never get made, urban waterways and shorelines without I hope that it encourages us all to imagine having to tear the whole thing down and richer, more alive shorelines in the city. start over. into human constraints of what qualifies as a “site” or not. While the ecological function of the Ship Canal will likely never be fully restored, it is important to consider the restoration options that are available to us. We tend to view the urban built environment as static, but that’s not always the case - can we find the areas of flexion, and push them to their limits?

This project attempted to do just that, and provide some answers to questions that have yet to be asked.

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